This section provides background information related to the present disclosure which is not necessarily prior art.
Strut-type suspension systems are well known in the motor vehicle industry. A telescopic strut assembly normally incorporating a hydraulic damper is used as one of the locating members for the wheel of the motor vehicle. A strut assembly typically includes a coil spring concentrically disposed around a shock absorber. The coil spring extends between an upper spring seat which is a part of a top mount assembly for the strut assembly and a lower spring seat which is attached to the shock absorber of the strut assembly.
The lower spring seat can be a single piece made of metal or plastic. A plastic spring seat is light weight than its metal counterpart. The lower spring seat typically includes an annular member that supports the lower end of the spring and a tubular member which extends from the annular member. The tubular member is designed to interface with an outer tube of the shock absorber. For example, FIG. 1 illustrates a lower spring seat 200, which is made of plastic, disposed about an outer tube 202 of a shock absorber. The lower spring seat 200 is retained by a support ring 204 which is welded to the outer tube 202. More particularly, a tubular member 206 of the lower spring seat 200 abuts the support ring 204.
The spring seat supports and maintain the correct position of the spring under various driving conditions of the vehicle. The spring seat resists braking loads, wear, abrasion, changing loads and hits by stones and other debris. During severe impact in which the spring fails, the spring seat is designed to withstand and support the spring. For example, a lower spring seat made of plastic may include a steel or rubber pad disposed on the lower spring seat which absorbs the energy in the event the spring fails. To avoid using such a pad on the whole lower spring seat, a spring sleeve is also mounted on the spring. The spring sleeve delays any failure due to early corrosion. However, the use of the added components like the pad and the spring sleeve further increases the cost of the lower spring seat and the overall cost of a strut assembly in which it is incorporated.